Aromatic polycarbonate is a polymer exhibiting good transparency, mechanical properties (such as impact resistance) and flame retardance property. This polymer is widely applied to engineering plastics and construction material, however, the thermal processability of the polymer is not sufficient for certain applications.
Polylactic acid is a polymer possessing good biodegradability and tensile strength. This polymer is suitable for applications in the fields of biomedical materials and environmental-friendly materials. In addition, polylactic acid can be recycled easily. Lactic acid, the monomer of the polylactic acid, can be prepared by renewable natural resources (such as starch). Nevertheless, polylactic acid is not only a brittle and low impact resistance material, but also possesses a low melt viscosity.
Blending the aromatic polycarbonate and polylactic acid is a feasible method to combine the advantages of these two polymers, however, the poor compatibility between the polymers will cause a obvious phase separation and significantly reduce the mechanical properties of the blend.
JP2007056247, JP2006111858 and JP2006199743 disclosed a method to improve the performance of the blend of aromatic polycarbonate and polylactic acid by adding a compatibilizer, wherein, the compatibilizer comprises a graft copolymer based on acrylic resin or styrene resin, a copolymer based on glycidyl or anhydride, and a vinyl graft copolymer. Although the compatibilizer improved the mechanical properties of the blend of aromatic polycarbonate and polylactic acid, the compatibilizer increased the cost for preparing the blend of aromatic polycarbonate and polylactic acid.
JP2006028299 and EP1792941 disclosed a method to improve the compatibility of the blend of aromatic polycarbonate and polylactic acid by adding chain extender, wherein, the chain extender included diisocyanate, bisphenol A epoxy oligomer and carbodiimide. However, this method would significantly increase the molecular weight of the blend of aromatic polycarbonate and polylactic acid, increase the melt viscosity of the blend accordingly and make it more difficult to process the blend.
Therefore, an object was to provide an economical blend of aromatic polycarbonate and polylactic acid with improved mechanical properties, as well as to methods for preparing the same.
Moreover, it was an object to provide mechanical products and/or parts, electronic equipments and/or parts, construction materials and/or commodities comprising a blend of aromatic polycarbonate and polylactic acid, as well as uses of the blend of aromatic polycarbonate and polylactic acid in preparing mechanical products and/or parts, electronic equipments and/or parts, construction material, and/or commodities.